Manufacture of pig-iron



(No Model.)

J. F. BENNETT.

MANUBAGTURE 0F APIG IRON.

.Egj Patented May 27,1884..

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JOHN FRANCIS BENNETT, OF PITTSBURG, PENNSYLVANIA.

VIANUFACTURE OF PIG-IRON SPECIFICATION forming part of Letters Patent No. 299,103, dated May 27, 1&84.

Application filed April 25, 1883. ,(No model.)

Zio @ZZ whom, it may concern,.-

Be it known that I, Jol-IN FRANCIS BENNETT, of Pittsburg, in the county of Allegheny and .State of Pennsylvania, have invented a certain new and useful Improvement in the Manufacture of Manganese Pig-Iron 5 and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form part of this specification.

My invention relates to the production of manganese pig-iron and castings thereof5'and it consists of a method for producing a product thereof having superior chilling qualities. The object of my method is to make a product having a large proportion of carbon, by reason of the presence of manganese, and a minimum of silicon, whereby such a deep chill is secured in the pig-iron and its castings as is especially desirable for car-wheels and analogous uses in the arts. I have discovered that to attain lthis end the constituent elements composing the product should be present in the following proportion four per cent. manganese, 4.15 carbon, .05 silicon, .375 phosphorus and other metals, and 91.425 iron. I attain this object by the means illustrated in the accompanying drawings, in which- Figure 1 is an elevation, partly in section, of the plant essential to the operation of my invention; and Fig. 2 is a plan view of the same.

Similar letters refer to corresponding parts in both views.

A represents the blastffurnace to which the crude iron and manganese ores are fed. The blast-furnace is provided with tuyere-holes, through which tuyeres II H inject hot or cold air, received from suitable blowers by means of annular pipe G. A downcomer, K, conducts the waste gases from the furnace into the main underground flue.

B represents a common air reverberatory furnace, heated either by solid or gaseous fuel, and having an independent fireplace and chimney. The chimney I is provided with a damper, I', operated from the ground by chain I and lever I. The furnace B is connected with the blast-furnace A by trough A', by which the liquid pig-iron, 'having undergone the desired chemical changes in the latter, is introduced into the former. It is also connected with the pig-bed F by trough B, to convey the desiliconized manganese pig-iron therefrom to the pig-bed. A short spout, B, projects from the front of the furnace B, to convey desiliconized manganese pig-iron into a ladle, C.

(l is a large ladle, mounted in bearings C C', in which it is shifted by handle C. is connected by trough 0 with a mold, E, adapted for large castings.

Besides the iron ore fed to a blast-furnace in the ordinary production of pig-iron, I add manganese ore of such quality as to give about four per cent. of manganese in the resulting liquid pig-iron. From the blast-furnace I convey it to a reverberatory furnace, and keep it there until, by the action of the hot gases pass ing over it, silicon has been removed. Care must be taken to effect the removal of the mass from the reverberatory furnace at the proper time, which will be indicated when jets or candles of carbonic-oxidegas.flame are seen through colored glass by the workmen. When the metal is desiliconized, I convey it to the mold in case a large casting is required, or into a'large ladle when smaller castings are to be made, whence it is transferred to small ladles and transported to the casting-molds, or onto a pig-bed when pigiron is required.

I have learned that metallic manganese has the property of combining with carbon in greater quantities than metallic iron. For example, the best carbide of iron contains about 4.8 per cent. of carbon, whereas the best carbide of manganese approximates seven per cent. I add to the iron ore, as above stated, spiegel or ferro-manganese substantially without silicon, in such proportion that the resulting pig-iron shall contain about four per cent. of metallic manganese, by which the carbon will be increased about .1 per cent., and hence the chilling quality of the iron to this extent enhanced.

The percentage of manganese ore to be smelted with iron ore in a blast-furnace to give four per cent. of manganese in the resulting pig-iron varies with the quality of the iron ore and the mode of smelting, and would The ladle have to be determined by practice. The variations are as follows:

First. If the iron orcs contain as much as one per cent. of phosphorus, and are smelted with a comparatively cool blast of 800o Fahrenheit, part of the manganese cre would be taken up by the phosphorus and pass into the slag as phosphate of manganese, and part would go into the slag as silicate of manganese. Consequently it would require ore containing seven per cent. of metallic manganese to give four per cent. thereof in the finished product.

Second. If the same iron ores are smelted with a hot-blast of 1200o Fahrenheit, lthe same proportion of manganese would be taken up by the phosphorus, but a smaller proportion would .go into the slag as -silicate of manganese. Therefore ore containing siX per cent. oi' metallic manganese would give four per cent. thereof in the finished product.

Third.. If the iron ores contain as little as .1 per cent. of phosphorus, and but little silicon, and are smclted with a blast of 1200O Fahrenheit, it would require ore containing but five per cent. of metallic manganese to give four per cent. thereof in the resulting pig-iron; hence the most favorable conditions for reducing the percentage of metallic manganese required in manganese cre to give a product containing a given per cent. of the same are iron ore comparatively free from phosphorus and containing a minimum of silica, smelted ata lowr pressure of blast raised to theY highy est attainable temperature.

The invention covered by this application differs from that embodied inmy invention patented to me May 20, 1884:, in three important particulars: First, a smaller percentage of manganic ore is fed with the iron ore; second,

the molten metal is retained for a shorter time in the reverberatory furnace, and by reason of feeding a lower percentage of manganic ore a correspondingly lower percentage of carbon is deposited in the liquid mass; and, third, the resulting product is different in containinga lower percentage of both manganese and carbon, a fixed percentage of phosphorus and other impurities, though the percentage of silicon is the same.

I am aware that heretofore iron and manganic ores have been smelted. together in a blast-furnace, and that molten metal has been -run from a smelting-furnace into an openhearth furnace and there desiliconized; and this I do not broadly claim.

Having thus fully described the process of obtaining my new product of desiliconized manganese pig-iron and castings thereof, together with an incidental description of the purposes of the latter, what I claim, and desire to secure by Letters Patent of the United States, is

In the manufacture of pig-iron and its castings, such as herein described, the process herein specified, which consists in smelting iron' and manganese ores in a blast-furnace, desiliconizing the duid mass in a reverberatory furnace, and then discharging the fluid contents onto a pig-bed or into a ladle for distribution to the casting-molds, substantially as described.

In testimony that I claim the foregoing as my own I affix my signature in presence of two witnesses. y

JOHN FRANCIS BENNETT.

Witnesses:

J. J. McCoRMrcK, THoMAs H. MCCORMIOK. 

